The conventional method for fusing a ball-striking plate of a titanium alloy material with a golf club head case of a stainless steel material is generally composed of the formation of a recess in the club head case to accommodate the ball-striking plate, which is then fused to the club head case by welding. Such a conventional method as described above is defective in design in that the ball-striking plate is fused securely with the case, and that there is always a small slit formed between the ball-striking plate and the case, and further that the fused area of the ball-striking plate and the case is vulnerable to crack caused by the impact of a ball hitting the ball-striking late, and still further that the weld mark left on the welded area must be removed by an additional finishing work which results in an increase in the cost of making the golf club head.